Method for preparation of sulfur-containing esters of phosphoric acid



Patented Sept. 28, 1954 D STAT METHOD FOR PREPARATION OF SULFUR- CONTAINING ESTERS OF PHOSPHORIC ACID N. Y., a corporation of New York No Drawing. Application September 28, 1951, Serial No. 248,893

Claims.

This invention relates to new sulfur-containing esters of phosphoric acid and. to the preparation of such compounds.

These new sulfur-containing phosphoric acid esters conform to the general formula RS-(OR)2 in which R. represents an alkyl, substituted alkyl or cycloalkyl radical and R represents an alkyl, substituted alkyl, cycloalkyl or alkenyl radical. In the new compounds, typical examples of R are methyl, ethyl, normal-butyl, tertiary-butyl, betachloroethyl, triphenylmethyl and cyclohexyl.

amounts to prepare the novel sulfur-containing phosphoric acid esters of the invention.

High yields of the desired sulfur-containing esters are obtained by carrying out the reaction in the presence of an inert solvent, preferably one lower boiling than the phosphoric acid ester or esters produced. Suitable inert solvents include ethylene dichloride, ethyl ether, petroleum ether, carbon tetrachloride, toluene and benzene. W hen reaction is completed, lower boiling solvent so used may be recovered for reuse by simple distillation at atmospheric or lower pressure.

The reaction may be carried out at any temperature up to the decomposition point of the Typical examples of R are ethyl, butyl, beta reactants. Generally, the reaction is quite chloroethyl, methyl, allyl and cyclohexyl. vigorous during the addition of the reactants, A sulfur-containing phosphoric acid ester of and cooling is desirable to retard the reaction. the general formula given above may be prepared In other cases, gentle warming is required to according to certain aspects of the invention by initate reaction. reacting an organic phosphite of the general As may be seen from the equation illustrating formula the reaction of the organic phosphites with the (R'OOsP organic sulionyl chlorides, phosphoric acid esters in which R has the meaning shown above, either of the gener a1 formula with an organic sulfonyl chloride of the general (R'O) formula 0 9 in which R has the meaning shown above, are produced during the course of the reaction. These gi fii gfi g sulfenyl chlonde of the phosphoric acid esters are well known articles of Rs C1 commerce finding usage, for example, as solvents 3 0 or plasticizers. Since heretofore, these esters in which R has the meaning shown above, and have not been produced by such a reaction, their recovering said sulfur-containing phosphoric acid preparation constitutes another feature of our ester. invention. The phosphoric acid esters may be The reaction between the organic phosphites separated from other reaction products by any and the organic sulfonyl chlorides takes place in suitable method such as by vacuum distillation accordance with the following equation: usually at a temperature higher than employed for recovery of preferred lower boiling solvent. As is apparent from the equation illustrating 0)a BS0201 )i+ )3PO the reaction of the organic phosphites with the The reaction between the organic phosphites 40 organic sulfenyl chlorides, phosphoric acid esters and the organic sulfenyl chlorides is represented r not p u as y-p Thus wh n the by the following equation; formation of by-product phosphoric acid esters is not desired, it may be preferred to produce 7 H the sulfur-containing phosphoric acid esters (3/0? R801 Its-HOBO i5 characteristic of the invention by use of the sul- The lower t 1 1 phosphites Such as i t l fenyl chloride reaction. When a lower trialkyl tributyl and tri (betachloroethyl) phosphites are phosphite r other ph phite forming a r l preferred reactants, but other phosphites of the tively vQlatile Organic Chloride is employed in general formula given above, including mixed reaction with the organic sulfenyl chloride, rephosphites containing different alkyl, substituted y 0f DrOdllGt Concentrated in Sul t alkyl, cycloalkyl or alkenyl radicals, may be effecing phosphoric acid ester y be fi d ea y tively employed. J and economically by simple heating or distilla- It is preferred that the organic phosphite and tion of the reaction mass at low temperature organic sulfonyl chloride or organic sulfenyl chlosuitable for driving off such organic chloride and. ride be employed in approximately stoichiometric solvent if present.

The following examples are given for the purpose of illustrating the present invention, but are Parts are by weight. not intended to be limiting on the scope thereof.

Example 1.-50 parts of triethyl phosphite were added slowly with stirring to a solution of 16 parts of normal-butanesulfonyl chloride in 84 parts of ethyl ether, the temperature being maintained below 30 C. The resulting solution was heated on a steam bath for hours to complete the reaction and to remove the ether solvent and the ethyl chloride formed during the reaction. The solution was then vacuum distilled to remove first triethyl phosphate and then the sulfur-containing phosphoric acid ester having the formula C4H9S: E (OO2H5)2 The sulfur-containing phosphoric acid ester, a colorless liquid distilling at 100 to 115 C. at 5 mm. mercury pressure, constituted 22 parts (97% of theory).

In another run, normal-butanesulfonyl chloride was reacted with tri (betachloroethyl) phosphite. The betachloroethyl chloride formed during the reaction was removed by heating, leaving a product comprising tri (betachloroethyl) phosphate and the sulfur-containing ester having the formula Example 2.33.2 parts of triethyl phosphite were added dropwise with stirring to a solution of 24.9 parts of tertiary-butanesulfenyl chloride in 250 parts of carbon tetrachloride, the temperature being maintained below 25 C. The tertiarybutanesulfenyl chloride was prepared by the method described in Industrial and Engineering Chemistry, May 1950, page 919. The resulting solution was allowed to stand overnight at room temperature and was then heated at reflux for approximately 6 hours to remove the carbon tetrachloride solvent and the ethyl chloride formed during the reaction. The residue was fractionated, and a product comprising the sulfur-containing phosphoric acid ester having the formula but containing no by-product triethyl phosphate was removed. The sulfur-containing phosphoric acid ester, a colorless liquid, constituted parts (66% of theory).

Example 3.- parts of triethyl phosphite were added dropwise with stirring to a solution of 24.9 parts of tertiary-butanesulfenyl chloride in 200 parts of petroleum ether, the temperature being maintained below 25 C. The tertiarybutanesulfenyl chloride was prepared by the method described in Industrial and Engineering Chemistry, May 1950, page 919. The resulting solution was allowed to stand at room temperature for 48 hours and was then refluxed for 3 hours to remove the petroleum ether solvent and the ethyl chloride formed during the reaction. The residue was fractionated, and a product comprising the sulfur-containing phosphoric acid ester having the formula 0 U 64 9 (0 C2H5)2 was obtained. The product, a colorless liquid, constituted 31 parts (69% theory).

Other aliphatic as well as cycloparafilnic sulfonyl and sulfenyl chlorides may be used as reactants in the above examples including methyl, ethyl and cyclohexylsulfonyl chlorides and methyl, betachloroethyl and triphenylmethylsulfenyl chlorides. Likewise, other organic phosphites, such as tributyl and tricyclohexyl phosphites may be employed in the examples.

Products of the type produced by the invention find valuable application for a number of purposes, including, but without limitation, as solvents or plasticizers, and as intermediates for a wide variety of mercaptans which are obtainable directly by hydrolysis of the novel sulfur-containing phosphoric acid esters characteristic of the invention.

We claim:

1. A method of preparing a sulfur-containing phosphoric acid ester of the general formula RSl (OR')2 in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals and R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, which includes the step of reacting an organic phosphite of the general formula in which R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, with an organic chloride of the group consisting of organic sulfonyl chlorides of the general formula RSOzCl and organic sulfenyl chlorides of the general formula RSCl in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals.

2. A method of preparing a sulfur-containing phosphoric acid ester of the general formula in which R is a member of the group co misting of alkyl, substituted alkyl and cycloallzyl radicals and R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, which comprises reacting an organic phosphite of the general formula in which R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, with an organic sulfonyl chloride of the general formula in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals. 3. A method of preparing a sulfur-containing phosphoric acid ester of the general formula Rs-] (OR )2 in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals and R is a member or" the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, which comprises reacting an organic phosphite of the general formula (RO)3P in which R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkcnyl radicals, with an organic sulfonyl chloride of the general formula RSOzCl in which R, is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals, and recovering said sulfur-containing phosphoric acid ester from the reaction mixture.

4. The process of claim 3 in which the organic phosphite is reacted with the organic sulfonyl chloride in ratio of about 3 mols of organic phosphite to 1 mol of organic sulfonyl chloride.

5. The process of claim 4 in which the reaction is carried out in the presence of an inert solvent.

6. A method of preparing a sulfur-containing phosphoric acid ester of the general formula RSI|EI(OR)2 in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals and R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, which comprises reacting an organic phosphite of the general formula in which R is a member of the group consisting of alkyl, substituted alkyl, cycloalkyl and alkenyl radicals, with an organic sulfenyl chloride of the general formula RSCl in which R is a member of the group consisting of alkyl, substituted alkyl and cycloalkyl radicals, and recovering said sulfur-containing phosphoric acid ester from the reaction mixture.

7. The process of claim 6 in which the organic phosphite is reacted with the organic sulfenyl 6 chloride in ratio of about 1 mol of organic phosphite to 1 mol of organic sulfenyl chloride.

8. The process of claim '7 in which the reaction is carried out in the presence of an inert solvent.

9. A method of preparing the sulfur-containing phosphoric acid ester having the formula i O4HnSP(OCzHa)2 which comprises reacting triethyl phosphite with butanesulfonyl chloride in the ratio of about 3 mols of triethyl phosphite to 1 mol of butanesulfonyl chloride in the presence of an inert solvent, and recovering said sulfur-containing phosphoric acid ester from the reaction mixture.

10. A method of preparing the sulfur-containing phosphoric acid ester having the formula C H9SI E (OC2Hs)2 which comprises reacting triethyl phosphite with butanesulfenyl chloride in the ratio of about 1 mol of triethyl phosphite to 1 mol of butanesulfenyl chloride in the presence of an inert solvent, and recovering said sulfur-containing phosphoric acid ester from the reaction mixture.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,508,364 Bell May 23, 1950 2,514,150 Bell July 4, 1950 OTHER REFERENCES Pistschimuka: Ber. Deut. Chem, vol. 41, pp. 3854 to 3859 (1908).

Emmett: J. Chem. Soc., vol. 99, pp. 713 to 720 (1911). 

1. A METHOD OF PREPARING A SULFUR-CONTAINING PHOSPHORIC ACID ESTER OF THE GENERAL FORMULA 